This invention relates to a bottle for hot filling use, and more particularly to a bottle equipped with vacuum absorption panels in the bodies of the bottle that can be covered with a full shrink label.
Coloring PET bottles in green or other colors is practiced so as to protect the bottle content from UV rays. Since, however, the use of coloring agents is not preferable for the reutilization of PET, there is a demand for colorless PET bottles.
Thus, there has been a proposal to use a shrink label having a UV-cut effect. A problem has arisen here. If a full shrink label is wrapped around a prior-art bottle, the tightening force of the label inhibits the vacuum absorption panels of a conventional bottle to recover to their original position. When such a bottle is opened, the liquid surface does not drop from its level before the bottle opening.
Now referring to FIG. 6, which shows an example of a prior-art bottle, B is a colorless, transparent bottle blow-molded in the biaxial orientation by using a PET resin. The bottle comprises neck, shoulder and body having a square cross-section, and bottom. A vacuum absorption panel (b) is disposed in each body wall (a) of the upper and lower bodies.
As shown in FIGS. 6 and 7, the vacuum absorption panel (b) comprises a gutter (c) running along the four sides of the square panel and connecting with the body wall; and four slopes (d) gathering together in the central area and surrounded by the gutter (c)
When pressure inside the bottle is reduced, the gutter (c) and four slopes (d) are deformed with the connection line between the vacuum absorption panel (b) and the body wall (a) working as the support. This deformation of the gutter (c) and four slopes (d) gives the vacuum absorption action to the panel.
If bottles are wrapped with a shrink label up to the bottleneck after the content has been cooled, then the body walls (a) are constricted laterally by the label""s tightening force. If this happens, there will be further deformation of the vacuum absorption panels (b), which have already been deformed by the reduced pressure.
Therefore, the problem is that, when the cap is opened at room temperature, the liquid level does not lower, but instead, liquid splashes out of the neck.
The full shrink label having the UV cut effect had likewise such a problem that this label could not be utilized together with prior-art bottles.
The object of this invention is to provide a PET bottle having structurally improved vacuum absorption panels in the body portion so as to increase the panels"" resistance to the constricting force of the shrink label, to secure the force of restitution for the panels, and thereby to allow the liquid level in the bottle to lower when the cap is opened.
This invention is characterized in that each vacuum absorption panel of the bottle for hot filling use has a configuration comprising multiple, flat and variable surfaces, which somewhat stand back from the plane of the corresponding body wall; and multiple, horizontal and grooved ribs having respectively a curved bottom with the middle portion of the bottom being slightly uplifted, and with each rib being placed under a variable surface in an alternately disposed manner.
The bottle according to this invention is characterized in that a full shrink label is fitted to the bottle over the area from the shoulder down to the lower end of the body, and that the full shrink label has a UV cut effect to protect the bottle content from UV rays.